This invention relates to a yo-yo, particularly to one having a few components and low percentage of wear and tear.
Conventional yo-yoes may be classified into two kinds according to structure. One kind has a simple structure, and the other has a clutch mechanism.
The first simple kind of yo-yo includes a male half and a female half, and a shaft fixed on the male half for a string to be tied thereon. In playing, the string tied on the male shaft has its free end attached with a ring for a finger of a player to fit in. Then the player pinches a yo-yo between the thumb and the middle finger, and then throws the yo-yo, letting the yo-yo rotate swiftly and move up and down by means of the string wound around the male shaft repeatedly, giving amusement to the player. In order to let the yo-yo continue to move up and down, the player has to pull up the yo-yo quickly the moment when the male half with female half comes to the end of the string, as the shaft is always stationary. Then the male half and the female half together may move up to the hand of the player again. Otherwise, the male half and the female half may not move up but stop, with the yo-yo interrupted in playing and amusement cooled off. Although this kind of yo-yo has an advantage of a simple structure with a few components, it is rather hard to handle, gradually going out of fashion.
The second kind of yo-yo having a clutch mechanism is disclosed in a U.S. Pat. No. 4,332,102. Its structure and operation are as follows.
1. It includes two yo-yo halves 10, 12, a central shaft 14, a bearing pulley 44, two clutch members 16, 18, two compressing springs 22, 24, two weighted balls 30, 32, and a central hub 20 as main components combined together. The central shaft 14 passes through a shaft hole around a recession 42 of the yo-yo half 12, a shaft hole (not numbered) of the bearing pulley 44, an opening 50 of the yo-yo half 10, and the shaft hole (not numbered) of the central hub 20, and an exploded perspective view is shown in FIG. 1.
2. The clutch members 16, 18 respectively have a curved recess (not numbered) to correspond to each other for an end of the compression spring to rest on for pinching a friction surface 46 of the bearing pulley 44. The clutch members 16, 18 further respectively have a pin 26, 28 located in a diagonal direction and a weighted ball 30, 32 positioned in a diagonal direction. Then the yo-yo half 10 has two opposite pin holes 52, 54 for the pins 26, 28 of the clutch members 16, 18 to fit therein so that the clutch members 16, 18 may bias to alter their position by means of the pin holes 52, 54.
3. The central shaft 14 is a little smaller than the shaft hole of the bearing pulley 44, and the movement of the bearing pulley 44 is controlled by the two clutch members 16, 18. The bearing pulley 44 further has an annular groove for tying the string 45 as shown in FIG. 4.
4. As for the operation of the yo-yo, when the yo-yo is thrown to swiftly rotate, the clutch members 16, 18 produce centrifugal force to compress the compressing springs 22, 24 by means of the weight of the balls 30, 32, permitting the bearing pulley 44 free not pinched to rotate idle. On the contrary, when the centrifugal force gradually diminishes to less than the elasticity of the compressing springs 22, 24, the springs 22, 24 recover to push the clutch members 16, 18, which may pinch the friction surface 46 of the bearing pulley 44, forcing the yo-yo rotates upward to go back to the hand of the player. So this kind of yo-yo is easier to handle than the first simple kind described above. In addition, when the yo-yo rotates idle, a special trick like idle rotation can be effected, increasing amusing feeling.
Though the second kind of yo-yo of a clutch structure has an advantage of easy handling, it has rather a little too many components to make its structure complicated and high percentage of friction, causing the curved surface of the clutch members 16, 18 contact irregularly with the friction surface 46 of the bearing pulley 44 in friction, forming a disadvantage of high wear and tear.